The company announced the expansion Tuesday evening, noting that customers in the Baltimore, Dallas, Indianapolis and Philadelphia areas will also now be able to have orders delivered on the same day if purchased online by noon.

To receive unlimited eligible items on the same day, Amazon Prime members must pay a flat $5.99 shipping fee per order. Those without a Prime membership pay an $8.99 fee plus another 99 cents per item.

Customers in Seattle, San Francisco, Los Angeles, and Phoenix already had these same-day options since May. Only Boston and Chicago have same-day shipping, but not seven days a week with the $5.99 unlimited item shipping fee deal.

Amazon, which offers some sort of same-day shipping option in 12 markets, noted today that there are now more than one million eligible products for same-day delivery.

This is the latest move by Amazon to narrow the gap between its website and customers’ doorsteps, attempting to rival the immediacy of traditional retailers, with the convenience of shopping online. Amazon’s attention-getting drone delivery initiative is also a long-term part of this effort.

It’s also another reason for customers to purchase a $99/year Prime membership, which features free two-day shipping, along with Amazon Prime Instant Video and Kindle book rentals, among other benefits.

Taylor Soper is a GeekWire staff reporter who covers a wide variety of tech assignments, including emerging startups in Seattle and Portland, the sharing economy and the intersection of technology and sports. Follow him @taylor_soper and email taylor@geekwire.com.